When producing GCr15 bearing steel ϕ50 ~75 mm bar

there is center porosity in rolled bar. A numerical simulation is carried out to study the penetration of effective strain in the core of bar and optimize the rough rolling pass technology

increase the reduction of the first two passes from original 21 mm and 58 mm to 51 mm and 85 mm respectively

and reduce the third pass from 60 mm to 34 mm. Through the effective strain value gradually increases with the increase of the pass

the tensile stress in the bar becomes compressive stress after the optimized process

and the uniformity of deformation is also obtained to promote the deformation of core of casting slab be available to the closure of the center porosity. After the process optimization

the qualified rate by ultrasonic detection of bearing steel increases from original 93.25% to 96.06%.